You have a hydraulic self-leveling suspension, which is why no one carries aftermarket struts.
If you wish to retain the system, perhaps you should consider popping in new Nitrogen cells? If you've never changed them, they might very well be shot-however, your symptoms aren't consistent with blown cells, so I wonder....
Are your rear hydro struts (shocks) leaking?
"If everything seems under control, you're simply not going fast enough" --Mario Andretti
1995 E500 street car
1986 Porsche 944 Turbo S track car